There are a variety of trailer hitches and towing attachments in use in the marketplace today. A ball-type trailer hitch is fairly common and can be either permanently or temporarily-attached to the frame or bumper of a vehicle. Many boat trailers, camping trailers, and moving trailers employ a ball-type attachment.
A ball-type trailer hitch can be permanently attached to a motor vehicle by welding or bolting a tongue to the underside or frame of a motor vehicle, and mounting a 2-inch ball on the portion of the tongue that extends beyond the vehicle.
Alternatively, a ball-type trailer hitch may also be permanently attached to a vehicle by bolting or welding hollow tubing to the underside of a motor vehicle. Typically, a tube having inner dimensions of approximately 11/2 or 2 inches by 11/2-2 inches protrudes from beneath a vehicle. A second tube, having outer dimensions slightly smaller than the opening in the tube attached to the vehicle is inserted into the tube attached to the vehicle. A steel pin, or other suitable fastener, is fed through both sets of steel tubes and serves to hold the inserted tube in place. The pin is typically 1/2-1 inch in diameter. A ball-type trailer hitch is affixed to the protruding end of the inserted steel tubing, and provides a point of attachment for a trailer.
This type of trailer hitch is typically rated at about 500 lb. tongue weight, and a 10,000 lb. load.
The tube-type trailer hitch attachment has also been used to mount bicycle racks, motorcycle racks, and other carrying devices to a vehicle. The tube-type hitch attachment has become more popular in recent years because of the versatility in allowing a vehicle owner to install a single-style hitch which can accommodate a variety of carrying or towing needs. One disadvantage of the tube-type hitch attachment is the movement and consequent noise caused by the inserted tube shaking or vibrating within the surrounding tube.
In order to allow the inserted tube to be readily removed from the hitch assembly, it is necessary that the inserted tube be sufficiently smaller than the surrounding hitch tube. Otherwise, frictional forces acting upon the inner tube restrict its removal and thereby increases the burden of disengaging the towing assembly. Conversely, where the inner tube is sized to decrease the frictional force so that removal is facilitated, the inner tube may bounce within the outer tube thereby creating oscillation and noise or rattle. This rattle can be extremely distracting to the driver of the vehicle, especially if the driver is not familiar with the movement and noise commonly made by trailer hitches.
The movement and consequent rattle can cause the driver to pay excessive attention to the trailer, or other carrying apparatus inserted in the hitch tube. This distraction serves as both an annoyance and a danger to the driver, as the driver's full attention is no longer devoted to other vehicular traffic, road conditions, and pedestrian traffic. In fact, the rougher the road conditions, the more trailer hitch will tend to move and rattle because of the inertia developed by the apparatus attached to the inserted tube.
A need therefore exists for a trailer hitch insert tube which minimizes or eliminates movement and noise generated by the trailer hitch.